1. Field of the Invention
The present invention relates to manipulator shoulder mechanism and more specifically to a pair of shoulder mechanisms provided for a self-maintenance type two-arm manipulator equipped in atomic energy facilities, for instance, which are always in danger of radioactivity contamination whenever an operator or a repair man has access thereto.
2. Description of the Prior Art
In the two-arm manipulator, in usual a plurality of power units such as motors are mounted on each of both the right hand and left hand shoulder sections of a slave manipulator in order to actuate plural joints corresponding to shoulder, elbow, wrist, etc. by the operation of a master manipulator. Since these motors are frequently driven and then stopped repeatedly and plural lead wire cables connected between the movable shoulder sections and a fixed frame are frequently transformed by the operation of the manipulator, bent or twisted, the motors often develop trouble and the lead wire cables are often damaged into disconnection. However, the damaged motors and cables are not easily removed and replaced with new ones because radioactive contamination makes dangerous a direct human access thereto and further the manipulator itself cannot remove and replace the damaged parts, it has been necessary to use another manipulator in order to remove and replace a defective motor or a defective lead wire cable with a new one, where the manipulator is equipped in a dangerous zone which refuses human access, thus resulting in a problem such that an additional equipment investment is required for maintenance of the manipulator.